An ultra-thin high-strength steel plate capable of being used at -60°C and its manufacturing method

Abstract

The invention discloses an ultra-thin high-strength steel plate that can be used under the condition of -60°C. The chemical composition is calculated as mass percent: C≤0.05, Si 0.20-0.40, Mn≤1.0, Nb+Ti+V≤0.15 , Cr≤0.30, P≤0.008, S≤0.0008, N≤0.002, O≤0.0010, H≤0.0001, P+S+[N]+[O]+[H]≤100ppm; Ni≤0.30, Cu≤0.30, Mo≤0.30, the balance is Fe and unavoidable impurities; the structure of the steel plate is uniform quasi-polygonal ferrite; the thickness is 4‑8mm, the yield strength is 460‑560MPa, the tensile strength is 550‑630MPa, and the impact energy at ‑60°C ≥200J. The technological process is KR hot metal pretreatment-converter-LF refining-RH vacuum degassing-slab continuous casting-slow cooling-rolling-cooling. The application fills up the production blank of high-strength, low-temperature and high-toughness ultra-thin steel plates in the market.

Description

technical field [0001] The invention belongs to the technical field of metallurgy and relates to an ultra-thin high-strength steel plate capable of being used in a -60°C environment and a manufacturing method thereof. Background technique [0002] With the need for lightweight engineering equipment, more and more low-alloy structural steel plates will be replaced by thin-gauge high-strength steel plates. However, in the manufacturing process of medium and heavy plates, extreme specifications are often the most technically difficult and demanding. At present, there are many studies on extra-thick high-strength steel plates, but for ultra-thin high-strength steel plates and their manufacturing methods, what has been reported There are few reports on ultra-thin high-strength steel plates that can meet the conditions of -60°C. [0003] In the industrial production process, the production of ultra-thin steel plates is very difficult, mainly in two aspects. One is that the compre...

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Problems solved by technology

However, in the manufacturing process of medium and heavy plates, extreme specifications are often the most technically difficult and demanding. At present, there are many studies on extra-thick high-strength steel plates, but for ultra-thin high-strength steel plates and their manufacturing methods, what has been reported There are few, and there are no reports on ultra-thin high-strength steel plates that can be used under the condition of -60 °C

[0003] In the industrial production process, the production of ultra-thin steel plates is very difficult, mainly in two aspects. One is that the compression ratio is too large (usually the compression ratio is 20-50 times), resulting in Concentrated segregation bands and dense distribution of inclusions in the finished steel plate , resulting in very unstable low-temperature impact energy, especially the impact energy of the 5mm-thick impact specimen is low, which cannot be used under the condition of -60°C; The reduction is too fast, and the production cannot be carried out according to the normal controlled rolling process. The rolling of conventional medium and heavy plate mills is extremely difficult, and the controlled rolling cannot be realized.

Under the combined effect of the two aspects, the low-temperature impact toughness of ultra-thin high-strength steel plates is unstable, and the strength is difficult to control. Therefore, there is no report on the production of ultra-thin high-strength steel plates with good low-temperature toughness by TMCP process

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